26 
OF granite. 
Upper Egypt. A very hard and beautiful granite of a reddish 
color, with black mica and a very small proportion of hornblende, 
was quarried at this place by the ancient Egyptians. Cleopatra’s 
neeilles and Pompey’s pillar at Alexandria are formed of it. Two 
obelisks now at Kome, .have withstood the attacks of the w'eather, 
and retained their original beauty after a lapse of three thou¬ 
sand years. Werner, mistaking the composition of a specimen of 
this Egyptian granite, and supposing it to be the binary com¬ 
pound of which we are speaking, gave the name of S 3 ’enite to 
those compounds of feldspar and hornblende, in which the latter 
ingredient is in distinct and separate crystals. By some Geolo¬ 
gists the name is restricted to rocks of this constitution, belonging 
to the overl)nng or trap famiU^. Verj’ handsome primitive 
S^'enite, is found in a number of different places in the neighbor¬ 
hood of the Universitj-'. In this the feldspar predominates, and 
is of a whitish color. But more commonly* it is the hornblende 
that is the prevailing ingredient, and communicating to the rocks 
its own color, and the property', in consequence of the quantity 
of iron it brings into their composition of decomposing into a 
red soil, it gives rise to the denominations of black rock and iron 
rock, by which they are commonly known. When the horn¬ 
blende predominates greatly, and is crystalline in its structure, 
the rock is the primitive trap of Werner. When there is a more 
intimate mixture of the ingredients, it cannot be distinguished 
from the greenstone of the old red sandstone formation, and 
finally, it is sometimes of so compact and uniform a structure that 
it has all the mineralogical characters of basalt, of which the na¬ 
tural walls in Rowan are an example. 
7. Granite composed of four Ingredients .—Of the granites 
containing four ingredients, and other rare and uncommon 
varieties, it will be enough to remark, that almost any four of the 
constituents of this rock, quartz, feldspar, mica, hornblende, 
chlorite, talc, and some other minerals, may sometimes be tound 
associated with each other, and that the glassy and compact are 
sometimes, though rarely, substituted for common feldspar. 
According to McCulloch, granite is an unslratified rock, and, 
in general, it exhibits no traces of stratification. \ et it is said by 
Jamieson to be sometimes stratified. This appears to be the case 
with some of the granites of Wake county, between Raleigh and the 
Neuse river, if not with others in the state of North Carolina. 
Granite is frequently' divided by seams or fissures into beds, prisms, 
and cuboidal masses. When into prisms, it is called columnar 
granite, of which there is an example on Haw River, between 
Chapel Hill and Pittsborough. Balls of a very' hard and indes¬ 
tructible granite arc sometimes imbedded in a softer variety, 
which undergoing decomposition, permit.^ the balls to fall out. 
'rids kind of structure may' Ire seen at the mill, a mile N. Last 
from Rockingham, in Richmond county'. That of Corsica, where 
this variety first attracted attention, is particularly remarkable for 
